Why has the euro gained an interest rate？A．It is the result of the rise of stock markets.B

Why has the euro gained an interest rate？

A．It is the result of the rise of stock markets.

B．Because bank shares have risen especially strongly.

C．Because the debts of governments such as Greece and Portugal have fallen.

D．Because the central banks began to buy governments debts in the markets.

请帮忙给出正确答案和分析，谢谢！